The currently commercialized lithium-ion batteries have allowed for the creation of practical electric vehicles, simultaneously satisfying many stringent milestones in energy density, lifetime, safety, power, and cost requirements of the electric vehicle economy. The next wave of consumer electric vehicles is just around the corner. Although widely adopted in the vehicle market, lithium-ion batteries still require further development to sustain their dominating roles among competitors. In this review, the authors survey the state-of-the-art active electrode materials and cell chemistries for automotive batteries. The performance, production, and cost are included. The advances and challenges in the lithium-ion battery economy from the material design to the cell and the battery packs fitting the rapid developing automotive market are discussed in detail. Also, new technologies of promising This article is protected by copyright. All rights reserved.2 battery chemistries are comprehensively evaluated for their potential to satisfy the targets of future electric vehicles.

This is the accepted version of the paper.This version of the publication may differ from the final published version. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 2 Rechargeable lithium ion batteries (LIBs) have long been considered as the most effective energy-storage technology and dominated portable electronic market for over two decades. Permanent repository link1, 2 Based on the intercalation mechanism, state-of-the-art Li-ion technology can exhibit a theoretical specific energy of ~400 Wh/kg, such as LiCoO 2 /graphite system. 3 However, it is urgent to explore new chemistries and materials that can significantly increase the cell energy density, considering the future demand for electronic vehicles and large-scale energy storage plants. 4,5 Graphite, a widely used anode material for the current LIBs, has a theoretical capacity of only 372 mAh/g, given a fully intercalated LiC 6 compound, which is one of the limiting factors for achieving high energy density of the cell 6 . In order to overcome such technical bottleneck, considerable effort has been devoted to design and synthesise new anode materials with higher theoretical specific capacity, such as transition metal oxides (SnO 2 , Co 3 O 4 ,Fe 3 O 4 ), Sn and Si 7 . However, all these materials suffer from severe volume variation during charge-discharge cycling, which results in serious pulverisation of the electrodes, and thus, rapid capacity degradation. For instance, Si has a high specific capacity of 4200 mAh/g if fully lithiated to Li 4.4 Si, however, it also shows a large volume expansion up to 400%. Such volume expansion causes huge mechanical stress of the electrode, and therefore, severely limits the lifetime of Si anode. Although various strategies have been proposed to enhance the structural stability of Si-based materials, including carbon or polymer coating 8,9 , nano-structuring 10-12 and hierarchical hybridization, [13][14][15] it is still very challenge to overcome the issue of the inherent volume change of these materials during cycling.Transition metal dichalcogenides (TMD) MX 2 (M=Mo, Ti, V, and W, X=S or Se) 16,17 with the similar feature of layered structure as graphite could have great potential for alternative anode materials. In general, MX 2 has strong covalent bonds within layers and weak Van der Waals forces between layers, which provide ideal space for intercalation of lithium ions. For instance, MoS 2 has much larger spacing between neighboring layers (0.615 nm) than that of graphite (0.335 nm) and weak van der Waals forces between the layers, which, in principal, may make the Li + diffuse easier. However, certain electrochemical properties of MX 2 can only be achieved in their 1-D or 2-D nanostructured crystals because of the relatively high resistance for Li-ion transport in their bulk form. In addition, the electron conductivity of th...

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Lithium–sulfur batteries are attractive for automobile and grid applications due to their high theoretical energy density and the abundance of sulfur. Despite the significant progress in cathode development, lithium metal degradation and the polysulfide shuttle remain two critical challenges in the practical application of Li–S batteries. Development of advanced electrolytes has become a promising strategy to simultaneously suppress lithium dendrite formation and prevent polysulfide dissolution. Here, a new class of concentrated siloxane‐based electrolytes, demonstrating significantly improved performance over the widely investigated ether‐based electrolytes are reported in terms of stabilizing the sulfur cathode and Li metal anode as well as minimizing flammability. Through a combination of experimental and computational investigation, it is found that siloxane solvents can effectively regulate a hidden solvation‐ion‐exchange process in the concentrated electrolytes that results from the interactions between cations/anions (e.g., Li+, TFSI−, and S2−) and solvents. As a result, it could invoke a quasi‐solid‐solid lithiation and enable reversible Li plating/stripping and robust solid‐electrolyte interphase chemistries. The solvation‐ion‐exchange process in the concentrated electrolytes is a key factor in understanding and designing electrolytes for other high‐energy lithium metal batteries.

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